Many media types are typically provided in a streaming mode, for example movies and audio. An advantage of streaming is that there is substantially no delay at a receiver before the media can be previewed, providing the media stream is sent in a manner synchronized to the viewing. If a user is required to wait for a media stream to repeat itself, for example in a carousel transmission system, the delay is as long as the transmission repeat time.
Another type of media dissemination method is multicasting, which may be combined with streaming. A single copy of the media stream is broadcast to a plurality of receivers. In some implementations, a complete file is transmitted by multicasting, without streaming, or is repeatedly transmitted.
Another type of data dissemination method is “on-demand” transmission. The transmission of data is synchronized with a request by a user. This type of dissemination is provided by unicasting (point to point connection). Alternatively, a receiver can select a start time, out of a small number of available times, at each of which times a complete retransmission of the data is performed. A particular application of “on-demand” dissemination is cable broadcasting of movies. In some implementations, a complete file may be transmitted “on-demand”, for viewing when convenient. In such a file transmission system, if a media file size is FS and an available transmission bandwidth is TB, a minimally expected delay before the file can be played back is FS/TB.
The following references describe methods of video on demand, their disclosures are incorporated herein by reference:
Darrell D. E. Long, Jehan-Francois Paris, Steven W. Carter “http://cs1.cse.ucse.edu/projects/video-on-demand/” present insight regarding video on demand and different transmission protocols (Harmonic Broadcasting, Pagoda Broadcasting), available on Jan. 9, 2001.
C. C. Aggarwal and J. L. Wolf and P. S. Yu. “A Permutation-Based Pyramid Broadcasting Scheme for Video-On-Demand Systems”. Proc. Of the IEEE Int'l Conf. On Multimedia Systems. June 1996.
C. C. Aggarwal and J. L. Wolf and P. S. Yu. “On Optimal Batching Policies for Video-on-Demand Storage Server” Proc. Of the IEEE Int'l Conf. On Multimedia Systems. June 1996.
S. Viswanathan and T. Imielinski. “Metropolitan Area Video-On-Demand Service Using Pyramid Broadcasting”. IEEE Multimedia Systems. 4:197-208, 1996.
K. A. Hua and S Sheu. “Skyscraper Broadcasting: A New Broadcasting Scheme for Metropolitan Video-On-Demand Systems”. ACM SIGCOMM. September 1997.
A. Dan and P. Shahabuddin and D. Sitaram, “Scheduling policies for an on-demand video server with batching”. In Proc. Of ACM Multimedia, October 1994, pp. 168-179.
A. Dan and D. Sitaram and P. Shahabuddin, “Dynamic Batching Policies for an On-Demand Video Server”. In Multimedia Systems, 4:112-121, June 1996.
L. Gao, J. Kurose, D. Towsley, “Efficient Schemes for Broadcasting Popular Videos”, Proceedings of NOSSDAV, Cambridge, UK, July 1998.
D. L. Eager and M. K. Vernon, “Dynamic Skyscraper Broadcasts for Video-On-Demand”, Technical Report #1375, Computer Science Department, UW-Madison, May 1998.